THE BASIC OPEN-HEARTH PROCESS.
TABLE XI-J. Elimination of Sulphur by Calcium Chloride.
Heat. Composition, per cent.
Sulphur. After adding CaCla. At time of tapping.
Initial. In steel. Si03. CaO, S. SiO,. CaO. S.
1 2 .87 .17 .047 .055 10.75 14.45 54.65 44.34 1.25 .53 10.20 11.76 48.98 47.80 .65 .57
TABLE XI-K. Detailed Data on the Elimination of Sulphur.
Open-hearth charge: 80 per cent, white iron, 20 per cent, scrap, the whole averaging about .30 sulphur.
Time of talcing sample. Composition of metal, per cent. Composition of slag per cent.
C. S. SiOa. CaO. . S.
After complete fusion ..... !o» .00 .10 .820 .181 .098 .040 18.80 15.00 11.60 10.80 49.24 49.60 55.64 57.00 .315 .578 .659 .646
] hour aftflir "m«ltlng . .....
4 hours after melting .....
Steel, 6% hours after melting
The sulphur after melting is higher than the calculated initial content, but this is probably due to incorrect sampling and to the absorption of sulphur from ore and gas, since the percentage of sulphur in the slag shows that a considerable amount was taken from the metal. After melting, the carbon was reduced to .20 per cent., and one hour later it was .09 per cent., but it was necessary to hold the charge in the furnace for four and one-half hours after complete decarburization, and to dose it with calcium chloride in the proportion of 50 pounds to the ton of metal, in order to remove the sulphur, a delay which is decidedly objectionable. The oxychloride, however, conferred fluidity upon the cinder, and made it possible to carry as high as 57 per cent, of CaO, and it is probable that this increased mobility and corresponding activity rendered the lime more efficacious in absorbing sulphur^/
A quantitative investigation on the slags from three of the charges given in Table XI-H showed that about 36 per cent, of